Multipoint electrical connector



March M, 31950 H. MILHENCH ETAL 2,500,292

MULTIPOINT ELECTRICAL CONNECTOR 4 Sheets-Sheet 1 Filed Jan. 10, 1946INVENTORS HARRY MILHENOH BENJAMEN CEClL GRESTY EDGAR EUGENE COMFORTATTOR N EY M H Q 1950 H. MlLHE NCH ETAL E fi fi MULTIPQINT ELECTRICALCONNECTOR Filed Jan. 10, 1 946 4 Sheets-Sheet z FIG/IA I Till/III:

INVENTORS HARRY HENCH BENJAM CECIL GRES EDGAR EUGENE COMFO ATTORNEY M,19% H. MILHENCH ETAL J 9 MULTIPOINT ELECTRICAL CONNECTOR Filed Jan. 10,1946 4 Sheets-Sheet s INVENTORS HARRY MILHENOH BENJAMEN CECIL GRESTYEDGAR EUGENE COMFORT ATTORNEY h H950 H. MILHENCH ETA]. 2

MULTIPOINT ELECTRICAL CONNECTOR Filed Jan. 10, 1946 I 4 Sheets-Sheet 4F1 11 J INVENTORS 'HARRY MILHENOH GRESTY 'BENJAMEN CECIL 51 52 EDGAREUGENE COMFORT ATTORNEY.

Patented Mar. 14, 1950 UNITED STATES PATENT OFFICE 2,500,292 MULTIPOINTELECTRICAL CONNECTOR Application January 10, 1946, Serial No. 640,282 InGreat Britain February 2, 1945 The present invention relates tomulti-point electrical connectors and particularly to equipment of thetype in which a plug carried by a piece of electrical apparatus adaptedto be removably supported on a rack or the like is arrangedautomatically to engage a jack on the rack when the piece of apparatusis placed in position. The invention finds particular application toautomatic switches, relay sets and the like as used in automatictelephone and similar light current signalling systems. For conveniencethe component parts of each connector will hereinafter be termed switchplug and shelf jack respectively.

Existing practice is for both switch plugs and shelf jacks to be rigidlymounted in their respective positions, and difiiculty is sometimesexperienced in ensuring the necessary accurate alignment therebetween,particularly when difiering pieces of interchangeable electricalapparatus are successively positioned in one mounting location. Thechief object of the invention is to enable this alignment problem to beovercome in a simple and ready manner.

According to one feature of the invention, in a multi-point electricalconnector arrangement suitable for detachably mounted electricalequipment which is supported independently of the contacts such asautomatic switches as used in telephone systems, the contacts formingone of the complementary parts of the connector are secured together toform a rigid unit which is arranged to have appreciable freedom ofmovement relative to its associated member which defines the mountedposition of the equipment.

According to another feature of the invention, in a multi-pointelectrical connector arrangement suitable for use in connection with themounting on racks of individual pieces of electrical equipment which aresupported independently of the contacts such as automatic switches asused in telephone systems, a plurality of the contacts on the rackassociated with one piece of equipment are mounted together to form arigid unit which is given appreciable freedom of movement relative tothe member which supports the piece of equipment so as to facilitatereplacement of the piece of equipment on the rack.

A further feature of the invention is that in a multi-point electricalconnector arrangement suitable for use in connection with the mountingon racks of individual pieces of electrical equipment which aresupported independently of the contacts such as automatic switches asused in telephone systems, a plurality of the contacts 4 Claims. (Cl.179-91) on an individual piece of equipment are mounted together to forma rigid unit which is given appreciable freedom of movement relative tothe member which is supported by the rack so as to facilitatereplacement of the piece of equipment on the rack.

The invention will be better understood from the following descriptionof three methods of carrying it into efiect, reference being had to theaccompanying drawings comprising Figs. 1 to 11 inclusive in which it isshown applied to automatic switches of the type disclosed in UnitedStates Patent No. 2,124,750 issued July 26, 1938, to R. N. Saxby, whichare adapted to be accommodated in mounting arrangements of the typedisclosed in United States Patent No. 2,067,246 issued January 12, 1937,to R. N. Saxby.

Of the drawings, Fig. 1 shows a side elevation of a movable orself-aligning shelf jack, Fig. 1A shows a plan view of the movable orself-aligning shelf jack looking in the direction E in Fig. 1, Fig. 2shows a side elevation of a switch cradle member mounted on a shelf,Fig. 2A shows a plan View of the switch cradle member looking in thedirection F of Fig. 2, Fig. 3 shows a side elevation of the cradle whenequipped with the self-aligning jack, and Fig. 3A shows an enlarged viewof a part of the apparatus shown in Fig. 3.

Fig. 4 shows a side elevation of part of a switch cradle member mountedon a shelf and equipped with a pair of shelf jacks, while Fig. 5 shows aside elevation of part of a switch mounting plate equipped with a switchframe and a pair of selfaligning switch plugs which differ from eachother in certain details.

Fig. 6 shows a plan view of the upper switch plug in Fig. 5, Fig. 7shows a sectional view on the line AA in Fig. 6, and Fig. 8 shows an endView looking in the direction B in Fig. 6.

Fig. 9 shows a plan view of the lower switch plug shown in Fig. 5, Fig.10 shows a sectional elevation on the line CC in Fig. 9, and Fig. 11shows an end elevation looking in the direction D in Fig. 9.

Referring now to Fig. 2, the cradle member I ll, which is U-shaped andmay be of pressed steel, is resiliently mounted on the shelf member itvia the intermediary of the rubber pads l2, l3 and M, the free ends ofthe cradle being linked by the curved bridge piece [5.

The self-aligning shelf jack shown in Figs. 1 and 1A is mounted on thecurved bracket l6 and comprises a block I! of ebonite or similarmaterial which is slotted to take the jack contact springs l 8 (only thethree left-hand pairs of con tact springs are shown in full). These areinsulated from each other by insulating strips 6 and are held inposition by an insulating strip [9, metal clamp plate 20 and fourcountersunk clamping screws which engage in threaded holes in thebracket It.

For the purpose of locating the self-aligning jack on the curved bridgepiece l as shown in Fig. 3, two or more tapped holes 5 are provided inthe latter to accommodate screws such as 21 which extend through slottedholes 2 in the bracket [6, the height of the holes 2 as seen in Fig. 1Abeing slightly larger than the largest diameter of the screw 2| so as toallow the screw 2i to pass loosely thru the hole 2. The ends of thescrews 2! which engage in the bridge piece I5 are of smaller diameterthan the portions extending thru the holes 2 shown in Fig. 3A. Thesescrews are screwed fully home into the tapped holes 5 so that theshoulder portion engages the bridge piece it through the holes 2 in thebracket IS. The nut 23 is then adjusted so as to give suitable play tothe bracket and the position is secured by the lock nut 22. It can beseen that the shelf jack mounted in the manner described above will havea limited longitudinal movement on the cradle member, the distance ofmovement being defined by the length A of the slottedholes 2 in thebracket it.

As an alternative to the screws such as 2| and nuts 22 and 23, use couldbe made of shouldered screws with the shoulder engaging the bracket I6instead of passing through the slotted holes 2 therein, the depth or"shoulder would then be such that the shelf jack would be always free toperform slight lateral movement to enable it accurately to align itselfwith the switch plug of any switch which was jacked in position into thecradle member concerned.

Considering now the embodiments of the invention in which the switchplug is movable rather than the shelf jack or in which both the switchplug and shelf jacks are movable, and referring first to Fig. 4, a pairof shelf jacks have been shown in this illustration in order thatconsideration may be given to the two difiering types of switch plugswhich may be required on switches of the type in question. The lowershelf jack 30 is movably secured to the curved bridge piece 3| of thecradle member 32 in the same manner as the switch jack in Figs. 1, 1A,2, 2A, 3, and 3A, while the upper shelf jack 33 is fixedly secured .tothe base of an inverted U-shaped bracket 34 in a well known manner, thefree ends of which are secured to the side members of the cradle 32.Thus it can be seen that shelf jack 30 is selfal-igning while shelf jack33 is not self-aligning. This arrangement would seldom be used on 'amounting arrangement, the switch jacks ordinarily being either bothself-aligning or both not self-aligning, but is used here as a goodillustration of alternate methods of application with self alig-ningswitch plugs.

Referring now to Fig. 5, the switch mounting plate 35 is assumed to beequipped with the-switch frame 36 together with two switch plugs, theupper one representing the standard type of plug which is fitted on allkinds of telephone type switching apparatus except where the plug isrequired to be fitted direct to the frame of aswitch I of the type inquestion while the lower plug represents the type evolved for fittingdirect to the switch frame.

Considering first the upper switch plu and referring to the variousviews thereof which are shown in Figs. 6, 7, and 8, the plug assemblycomprises the usual ebonite block 40, contact springs such as 4| (onlythe three left-hand pairs of contact springs are shown in full),insulating strip 42 and metal clamp plate 43, the assembly being heldtogether by the four clamping screws 44. In the usual arrangement (notshown) the countersunk clamping screws 44 screw downwardly through theplug bracket 45 into threaded holes in the plate 43, bracket 45 being inturn anchored to the switch mounting plate by means of a tongue 46,Figs. 5 and 6, integral with bracket 45 which engages a slot in themounting plate 35, the bracket being rigidly fixed thereto by screwssuch as 41, Fig. 5. To render the plug adjustable in accordance with theinvention the heads of the screws 45 are arranged to be countersunk inthe block 4! with the screws still threaded into the clamp plate 43 asshown, thereby forming a selfcontained plug assembly. Two or more slots18, Fig. 6, are provided in the bracket 45 through which extendshouldered screws 46 which pass through the ebonite block 40 and screwinto tapped holes in the clamp plate 33. The depth of the shoulder onthe screws 49 is such as to permit free lateral movement of the plugrelative to the bracket 65 so that it can align itself with the shelfjack springs on the non-self-aligning shelf jack 33 when the switch isjacked into position.

Referring now to the various views of the lower switch plug which areshown in Figs. 9, l0 and 11, the assembly of this plug as aself-contained unit is substantially the same as for the upper plug butthe bracket 58 differs in shape from bracket '45 in view of theconditions peculiar to its tment of the switch frame 36, Fig.5. Bracket50 is of box formation with a downwardly projecting flange portion 5!which carries two holes 52, Fig. 11, to enable it to be secured to theswitch frame by screws such as 53, Fig. 5. When the plug is beingassembled on to the switch frame, lugs 5S engage suitable slots in theassociated switch mounting plate 35. Free lateral movement of the plugis ensured by the shouldered screws 5'! which locate in slots 53 in thebracket 58 and extend through into threaded holes in the plug clampingplate :59. It will be noted that this plug is inverted compared with theupper plug, so as to enable the wiring tags to clear the bracketextension 51. The allowable lateral movement of the self-aligning shelfjack 3t and the lateral movement of the lower switch plug of Fig. 5permit easy alignment of the contact springs of the plugand jack whenthe switch is mounted on the frame.

As between either the self-aligning shelf jack or the-self-aligningswitch plug method for ensuring accurate alignment between switch plugsand shelf jacks, the use of the self-aligning switch plug offers theadvantage that switches, relay sets, and like pieces-of electricalapparatus so equipped will produce automatic alignment between theirplugs and the shelf jacks regardless of whether the shelves andassociated jacks are new or existing items, that is to say whether thejacks are of the self-aligningor fixed type.

We claim:

1. In a telephone mounting system, a rack, a switch, a multi-contactjack rigidly secured to said rack, a multi-contact plug having contactscorresponding to certain contacts of said jack, openings in saidswitchpa number of screws equal to the number of openings, each screwsmaller in diameter than the opening, means for securing said plug tosaid switch by said screws thru said openings so as to allow limitedmovement of the plug relative to the switch, and means for mounting saidswitch on said rack to cause the plug to engage the jack, said relativemovement permitting proper alignment oi? the corresponding contacts ofsaid jack and plug.

2. In a telephone mounting system, a rack, a switch, a multi-contactplug rigidly secured to said switch, a multi-contact jack havingcontacts corresponding to certain contacts of said plug, openings insaid jack, a number of screws equal to the number of openings, eachscrew smaller in diameter than the opening, means for securing said jackto said rack by said screws thru said openings so as to allow limitedmovement of the jack relative to the rack, and means for mounting theswitch on said rack to cause the plug to engage the jack, said relativemovement permitting proper alignment of the corresponding contacts ofsaid jack and plug.

3. In a mounting arrangement, a base, a member, a jack comprising aplurality of contacts mounted on said base, a plug comprising aplurality of contacts corresponding to the contacts of said jack mountedon said member, means for mounting said member on said base to causesaid plug contacts to engage said corresponding jack contacts, and meansfor securing said jack to said base to permit limited movement of saidjack relative to said base and for securing said plug to said member topermit limited movement of said plug relative to said member to therebyinsure proper alignment of said corresponding jack contacts and plugcontacts when said member is mounted on said base.

4. In a mounting arrangement, a base, a member, a multi-contact jack onsaid base, a multicontact plug on said member having contactscorresponding to the contacts on said jack, means for mounting saidmember on said base to cause said plug contacts to engage said jackcontacts, a first link securing said jack to said base to allow limitedmovement of said jack relative to said base, and a second link securingsaid plug to said member to allow limited movement of said plug relativeto said member, said relative movements permitting a proper alignment ofthe corresponding contacts of said plug and jack when said member ismounted on said base.

HARRY MILHENCH. BENJAMIN CECIL GRESTY. EDGAR EUGENE COMFORT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,418,171 Raettig May 30, 19221,587,120 Haddock June 1, 1926 1,771,088 Kessler et al July 22, 19302,067,246 Saxby Jan. 12, 1937 2,124,750 Saxby July 26, 1938 2,440,270Hecht Apr. 27, 1948

